類血管腫型線維性組織球腫の1例

A Case of Angiomatoid Fibrous Histiocytoma

はじめに

　類血管腫型線維性組織球腫（angiomatoid fibrous histiocytoma：以下，AFH）は全軟部組織腫瘍の0.3 ％と極めてまれな疾患であり 1），2020年のWHO分類において分化不明腫瘍の中間群（低頻度転移性）に分類されている 2）。今回われわれは，背景疾患に自閉症スペクトラム障害（autism spectrum disorder：以下，ASD）をもつ8歳女児の左前腕に発生したAFHの1例を経験した。臨床経過で腫瘍は縮小傾向を認め，良性腫瘍との鑑別を要したため，若干の文献的考察を加えて報告する。

　Angiomatoid fibrous histiocytoma (AFH) is an extremely rare soft tissue tumor and is classified as a tumor of unknown differentiation. We present a case of AFH on the left forearm of an 8-year-old girl with autism spectrum disorder. During the clinical course, the tumor showed a tendency to shrink, which required differentiation from a granuloma telangiectaticum. The results of a molecular biological analysis suggested the presence of the EWSR1-CREB1 fusion gene, which enabled the diagnosis of AFH. It can be difficult to diagnose AFH based on only the clinical course and histopathological findings. In this patientʼs case, after the diagnosis of AFH was made, an additional resection was performed with a 3-cm surgical margin. Further investigations of the optimal surgical margins for this tumor are merited.